1. Field
The subject matter disclosed herein relates to measurement of processing delay.
2. Information
Some mobile wireless devices estimate their current positions or locations by contacting nearby wireless devices, such as access points at stationary or substantially fixed positions or locations, or other mobile wireless devices. An access point, for example, may be stationary and at a known position. A mobile wireless device may estimate its distance from an access point by transmitting a packet to such an access point. Upon receipt of the packet, an access point may transmit an acknowledgement packet back to the mobile wireless device. Such a mobile wireless device may subsequently estimate its distance based on a measured round-trip delay from when a packet was sent to an access point and until an acknowledgement packet was received.
In order to precisely measure distance, a measurement of the round-trip time has to be accurate. However, an access point does not typically instantly transmit an acknowledgement packet upon receipt of a packet. Instead, an access point may perform some additional operations upon receipt of a packet and prior to sending an acknowledgement packet. Accordingly, there may be some processing delay by the access point prior to sending the acknowledgement packet.